1 /*
2 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
8 *
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_GCTASKMANAGER_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_GCTASKMANAGER_HPP
27
28 #include "runtime/mutex.hpp"
29 #include "utilities/growableArray.hpp"
30
31 //
32 // The GCTaskManager is a queue of GCTasks, and accessors
33 // to allow the queue to be accessed from many threads.
34 //
35
36 // Forward declarations of types defined in this file.
37 class GCTask;
38 class GCTaskQueue;
39 class SynchronizedGCTaskQueue;
40 class GCTaskManager;
41 class NotifyDoneClosure;
42 // Some useful subclasses of GCTask. You can also make up your own.
43 class NoopGCTask;
44 class BarrierGCTask;
45 class ReleasingBarrierGCTask;
46 class NotifyingBarrierGCTask;
47 class WaitForBarrierGCTask;
48 // A free list of Monitor*'s.
49 class MonitorSupply;
50
51 // Forward declarations of classes referenced in this file via pointer.
52 class GCTaskThread;
53 class Mutex;
54 class Monitor;
55 class ThreadClosure;
56
57 // The abstract base GCTask.
58 class GCTask : public ResourceObj {
59 public:
60 // Known kinds of GCTasks, for predicates.
61 class Kind : AllStatic {
62 public:
63 enum kind {
64 unknown_task,
65 ordinary_task,
66 barrier_task,
67 noop_task
68 };
69 static const char* to_string(kind value);
70 };
71 private:
72 // Instance state.
73 const Kind::kind _kind; // For runtime type checking.
74 const uint _affinity; // Which worker should run task.
75 GCTask* _newer; // Tasks are on doubly-linked ...
76 GCTask* _older; // ... lists.
77 public:
78 virtual char* name() { return (char *)"task"; }
79
80 // Abstract do_it method
81 virtual void do_it(GCTaskManager* manager, uint which) = 0;
82 // Accessors
83 Kind::kind kind() const {
84 return _kind;
85 }
86 uint affinity() const {
87 return _affinity;
88 }
89 GCTask* newer() const {
90 return _newer;
91 }
92 void set_newer(GCTask* n) {
93 _newer = n;
94 }
95 GCTask* older() const {
96 return _older;
97 }
98 void set_older(GCTask* p) {
99 _older = p;
100 }
101 // Predicates.
102 bool is_ordinary_task() const {
103 return kind()==Kind::ordinary_task;
104 }
105 bool is_barrier_task() const {
106 return kind()==Kind::barrier_task;
107 }
108 bool is_noop_task() const {
109 return kind()==Kind::noop_task;
110 }
111 void print(const char* message) const PRODUCT_RETURN;
112 protected:
113 // Constructors: Only create subclasses.
114 // An ordinary GCTask.
115 GCTask();
116 // A GCTask of a particular kind, usually barrier or noop.
117 GCTask(Kind::kind kind);
118 // An ordinary GCTask with an affinity.
119 GCTask(uint affinity);
120 // A GCTask of a particular kind, with and affinity.
121 GCTask(Kind::kind kind, uint affinity);
122 // We want a virtual destructor because virtual methods,
123 // but since ResourceObj's don't have their destructors
124 // called, we don't have one at all. Instead we have
125 // this method, which gets called by subclasses to clean up.
126 virtual void destruct();
127 // Methods.
128 void initialize();
129 };
130
131 // A doubly-linked list of GCTasks.
132 // The list is not synchronized, because sometimes we want to
133 // build up a list and then make it available to other threads.
134 // See also: SynchronizedGCTaskQueue.
135 class GCTaskQueue : public ResourceObj {
136 private:
137 // Instance state.
138 GCTask* _insert_end; // Tasks are enqueued at this end.
139 GCTask* _remove_end; // Tasks are dequeued from this end.
140 uint _length; // The current length of the queue.
141 const bool _is_c_heap_obj; // Is this a CHeapObj?
142 public:
143 // Factory create and destroy methods.
144 // Create as ResourceObj.
145 static GCTaskQueue* create();
146 // Create as CHeapObj.
147 static GCTaskQueue* create_on_c_heap();
148 // Destroyer.
149 static void destroy(GCTaskQueue* that);
150 // Accessors.
151 // These just examine the state of the queue.
152 bool is_empty() const {
153 assert(((insert_end() == NULL && remove_end() == NULL) ||
154 (insert_end() != NULL && remove_end() != NULL)),
155 "insert_end and remove_end don't match");
156 return insert_end() == NULL;
157 }
158 uint length() const {
159 return _length;
160 }
161 // Methods.
162 // Enqueue one task.
163 void enqueue(GCTask* task);
164 // Enqueue a list of tasks. Empties the argument list.
165 void enqueue(GCTaskQueue* list);
166 // Dequeue one task.
167 GCTask* dequeue();
168 // Dequeue one task, preferring one with affinity.
169 GCTask* dequeue(uint affinity);
170 protected:
171 // Constructor. Clients use factory, but there might be subclasses.
172 GCTaskQueue(bool on_c_heap);
173 // Destructor-like method.
174 // Because ResourceMark doesn't call destructors.
175 // This method cleans up like one.
176 virtual void destruct();
177 // Accessors.
178 GCTask* insert_end() const {
179 return _insert_end;
180 }
181 void set_insert_end(GCTask* value) {
182 _insert_end = value;
183 }
184 GCTask* remove_end() const {
185 return _remove_end;
186 }
187 void set_remove_end(GCTask* value) {
188 _remove_end = value;
189 }
190 void increment_length() {
191 _length += 1;
192 }
193 void decrement_length() {
194 _length -= 1;
195 }
196 void set_length(uint value) {
197 _length = value;
198 }
199 bool is_c_heap_obj() const {
200 return _is_c_heap_obj;
201 }
202 // Methods.
203 void initialize();
204 GCTask* remove(); // Remove from remove end.
205 GCTask* remove(GCTask* task); // Remove from the middle.
206 void print(const char* message) const PRODUCT_RETURN;
207 };
208
209 // A GCTaskQueue that can be synchronized.
210 // This "has-a" GCTaskQueue and a mutex to do the exclusion.
211 class SynchronizedGCTaskQueue : public CHeapObj {
212 private:
213 // Instance state.
214 GCTaskQueue* _unsynchronized_queue; // Has-a unsynchronized queue.
215 Monitor * _lock; // Lock to control access.
216 public:
217 // Factory create and destroy methods.
218 static SynchronizedGCTaskQueue* create(GCTaskQueue* queue, Monitor * lock) {
219 return new SynchronizedGCTaskQueue(queue, lock);
220 }
221 static void destroy(SynchronizedGCTaskQueue* that) {
222 if (that != NULL) {
223 delete that;
224 }
225 }
226 // Accessors
227 GCTaskQueue* unsynchronized_queue() const {
228 return _unsynchronized_queue;
229 }
230 Monitor * lock() const {
231 return _lock;
232 }
233 // GCTaskQueue wrapper methods.
234 // These check that you hold the lock
235 // and then call the method on the queue.
236 bool is_empty() const {
237 guarantee(own_lock(), "don't own the lock");
238 return unsynchronized_queue()->is_empty();
239 }
240 void enqueue(GCTask* task) {
241 guarantee(own_lock(), "don't own the lock");
242 unsynchronized_queue()->enqueue(task);
243 }
244 void enqueue(GCTaskQueue* list) {
245 guarantee(own_lock(), "don't own the lock");
246 unsynchronized_queue()->enqueue(list);
247 }
248 GCTask* dequeue() {
249 guarantee(own_lock(), "don't own the lock");
250 return unsynchronized_queue()->dequeue();
251 }
252 GCTask* dequeue(uint affinity) {
253 guarantee(own_lock(), "don't own the lock");
254 return unsynchronized_queue()->dequeue(affinity);
255 }
256 uint length() const {
257 guarantee(own_lock(), "don't own the lock");
258 return unsynchronized_queue()->length();
259 }
260 // For guarantees.
261 bool own_lock() const {
262 return lock()->owned_by_self();
263 }
264 protected:
265 // Constructor. Clients use factory, but there might be subclasses.
266 SynchronizedGCTaskQueue(GCTaskQueue* queue, Monitor * lock);
267 // Destructor. Not virtual because no virtuals.
268 ~SynchronizedGCTaskQueue();
269 };
270
271 // This is an abstract base class for getting notifications
272 // when a GCTaskManager is done.
273 class NotifyDoneClosure : public CHeapObj {
274 public:
275 // The notification callback method.
276 virtual void notify(GCTaskManager* manager) = 0;
277 protected:
278 // Constructor.
279 NotifyDoneClosure() {
280 // Nothing to do.
281 }
282 // Virtual destructor because virtual methods.
283 virtual ~NotifyDoneClosure() {
284 // Nothing to do.
285 }
286 };
287
288 class GCTaskManager : public CHeapObj {
289 friend class ParCompactionManager;
290 friend class PSParallelCompact;
291 friend class PSScavenge;
292 friend class PSRefProcTaskExecutor;
293 friend class RefProcTaskExecutor;
294 private:
295 // Instance state.
296 NotifyDoneClosure* _ndc; // Notify on completion.
297 const uint _workers; // Number of workers.
298 Monitor* _monitor; // Notification of changes.
299 SynchronizedGCTaskQueue* _queue; // Queue of tasks.
300 GCTaskThread** _thread; // Array of worker threads.
301 uint _busy_workers; // Number of busy workers.
302 uint _blocking_worker; // The worker that's blocking.
303 bool* _resource_flag; // Array of flag per threads.
304 uint _delivered_tasks; // Count of delivered tasks.
305 uint _completed_tasks; // Count of completed tasks.
306 uint _barriers; // Count of barrier tasks.
307 uint _emptied_queue; // Times we emptied the queue.
308 NoopGCTask* _noop_task; // The NoopGCTask instance.
309 uint _noop_tasks; // Count of noop tasks.
310 public:
311 // Factory create and destroy methods.
312 static GCTaskManager* create(uint workers) {
313 return new GCTaskManager(workers);
314 }
315 static GCTaskManager* create(uint workers, NotifyDoneClosure* ndc) {
316 return new GCTaskManager(workers, ndc);
317 }
318 static void destroy(GCTaskManager* that) {
319 if (that != NULL) {
320 delete that;
321 }
322 }
323 // Accessors.
324 uint busy_workers() const {
325 return _busy_workers;
326 }
327 // Pun between Monitor* and Mutex*
328 Monitor* monitor() const {
329 return _monitor;
330 }
331 Monitor * lock() const {
332 return _monitor;
333 }
334 // Methods.
335 // Add the argument task to be run.
336 void add_task(GCTask* task);
337 // Add a list of tasks. Removes task from the argument list.
338 void add_list(GCTaskQueue* list);
339 // Claim a task for argument worker.
340 GCTask* get_task(uint which);
341 // Note the completion of a task by the argument worker.
342 void note_completion(uint which);
343 // Is the queue blocked from handing out new tasks?
344 bool is_blocked() const {
345 return (blocking_worker() != sentinel_worker());
346 }
347 // Request that all workers release their resources.
348 void release_all_resources();
349 // Ask if a particular worker should release its resources.
350 bool should_release_resources(uint which); // Predicate.
351 // Note the release of resources by the argument worker.
352 void note_release(uint which);
353 // Constants.
354 // A sentinel worker identifier.
355 static uint sentinel_worker() {
356 return (uint) -1; // Why isn't there a max_uint?
357 }
358
359 // Execute the task queue and wait for the completion.
360 void execute_and_wait(GCTaskQueue* list);
361
362 void print_task_time_stamps();
363 void print_threads_on(outputStream* st);
364 void threads_do(ThreadClosure* tc);
365
366 protected:
367 // Constructors. Clients use factory, but there might be subclasses.
368 // Create a GCTaskManager with the appropriate number of workers.
369 GCTaskManager(uint workers);
370 // Create a GCTaskManager that calls back when there's no more work.
371 GCTaskManager(uint workers, NotifyDoneClosure* ndc);
372 // Make virtual if necessary.
373 ~GCTaskManager();
374 // Accessors.
375 uint workers() const {
376 return _workers;
377 }
378 NotifyDoneClosure* notify_done_closure() const {
379 return _ndc;
380 }
381 SynchronizedGCTaskQueue* queue() const {
382 return _queue;
383 }
384 NoopGCTask* noop_task() const {
385 return _noop_task;
386 }
387 // Bounds-checking per-thread data accessors.
388 GCTaskThread* thread(uint which);
389 void set_thread(uint which, GCTaskThread* value);
390 bool resource_flag(uint which);
391 void set_resource_flag(uint which, bool value);
392 // Modifier methods with some semantics.
393 // Is any worker blocking handing out new tasks?
394 uint blocking_worker() const {
395 return _blocking_worker;
396 }
397 void set_blocking_worker(uint value) {
398 _blocking_worker = value;
399 }
400 void set_unblocked() {
401 set_blocking_worker(sentinel_worker());
402 }
403 // Count of busy workers.
404 void reset_busy_workers() {
405 _busy_workers = 0;
406 }
407 uint increment_busy_workers();
408 uint decrement_busy_workers();
409 // Count of tasks delivered to workers.
410 uint delivered_tasks() const {
411 return _delivered_tasks;
412 }
413 void increment_delivered_tasks() {
414 _delivered_tasks += 1;
415 }
416 void reset_delivered_tasks() {
417 _delivered_tasks = 0;
418 }
419 // Count of tasks completed by workers.
420 uint completed_tasks() const {
421 return _completed_tasks;
422 }
423 void increment_completed_tasks() {
424 _completed_tasks += 1;
425 }
426 void reset_completed_tasks() {
427 _completed_tasks = 0;
428 }
429 // Count of barrier tasks completed.
430 uint barriers() const {
431 return _barriers;
432 }
433 void increment_barriers() {
434 _barriers += 1;
435 }
436 void reset_barriers() {
437 _barriers = 0;
438 }
439 // Count of how many times the queue has emptied.
440 uint emptied_queue() const {
441 return _emptied_queue;
442 }
443 void increment_emptied_queue() {
444 _emptied_queue += 1;
445 }
446 void reset_emptied_queue() {
447 _emptied_queue = 0;
448 }
449 // Count of the number of noop tasks we've handed out,
450 // e.g., to handle resource release requests.
451 uint noop_tasks() const {
452 return _noop_tasks;
453 }
454 void increment_noop_tasks() {
455 _noop_tasks += 1;
456 }
457 void reset_noop_tasks() {
458 _noop_tasks = 0;
459 }
460 // Other methods.
461 void initialize();
462 };
463
464 //
465 // Some exemplary GCTasks.
466 //
467
468 // A noop task that does nothing,
469 // except take us around the GCTaskThread loop.
470 class NoopGCTask : public GCTask {
471 private:
472 const bool _is_c_heap_obj; // Is this a CHeapObj?
473 public:
474 // Factory create and destroy methods.
475 static NoopGCTask* create();
476 static NoopGCTask* create_on_c_heap();
477 static void destroy(NoopGCTask* that);
478 // Methods from GCTask.
479 void do_it(GCTaskManager* manager, uint which) {
480 // Nothing to do.
481 }
482 protected:
483 // Constructor.
484 NoopGCTask(bool on_c_heap) :
485 GCTask(GCTask::Kind::noop_task),
486 _is_c_heap_obj(on_c_heap) {
487 // Nothing to do.
488 }
489 // Destructor-like method.
490 void destruct();
491 // Accessors.
492 bool is_c_heap_obj() const {
493 return _is_c_heap_obj;
494 }
495 };
496
497 // A BarrierGCTask blocks other tasks from starting,
498 // and waits until it is the only task running.
499 class BarrierGCTask : public GCTask {
500 public:
501 // Factory create and destroy methods.
502 static BarrierGCTask* create() {
503 return new BarrierGCTask();
504 }
505 static void destroy(BarrierGCTask* that) {
506 if (that != NULL) {
507 that->destruct();
508 delete that;
509 }
510 }
511 // Methods from GCTask.
512 void do_it(GCTaskManager* manager, uint which);
513 protected:
514 // Constructor. Clients use factory, but there might be subclasses.
515 BarrierGCTask() :
516 GCTask(GCTask::Kind::barrier_task) {
517 // Nothing to do.
518 }
519 // Destructor-like method.
520 void destruct();
521 // Methods.
522 // Wait for this to be the only task running.
523 void do_it_internal(GCTaskManager* manager, uint which);
524 };
525
526 // A ReleasingBarrierGCTask is a BarrierGCTask
527 // that tells all the tasks to release their resource areas.
528 class ReleasingBarrierGCTask : public BarrierGCTask {
529 public:
530 // Factory create and destroy methods.
531 static ReleasingBarrierGCTask* create() {
532 return new ReleasingBarrierGCTask();
533 }
534 static void destroy(ReleasingBarrierGCTask* that) {
535 if (that != NULL) {
536 that->destruct();
537 delete that;
538 }
539 }
540 // Methods from GCTask.
541 void do_it(GCTaskManager* manager, uint which);
542 protected:
543 // Constructor. Clients use factory, but there might be subclasses.
544 ReleasingBarrierGCTask() :
545 BarrierGCTask() {
546 // Nothing to do.
547 }
548 // Destructor-like method.
549 void destruct();
550 };
551
552 // A NotifyingBarrierGCTask is a BarrierGCTask
553 // that calls a notification method when it is the only task running.
554 class NotifyingBarrierGCTask : public BarrierGCTask {
555 private:
556 // Instance state.
557 NotifyDoneClosure* _ndc; // The callback object.
558 public:
559 // Factory create and destroy methods.
560 static NotifyingBarrierGCTask* create(NotifyDoneClosure* ndc) {
561 return new NotifyingBarrierGCTask(ndc);
562 }
563 static void destroy(NotifyingBarrierGCTask* that) {
564 if (that != NULL) {
565 that->destruct();
566 delete that;
567 }
568 }
569 // Methods from GCTask.
570 void do_it(GCTaskManager* manager, uint which);
571 protected:
572 // Constructor. Clients use factory, but there might be subclasses.
573 NotifyingBarrierGCTask(NotifyDoneClosure* ndc) :
574 BarrierGCTask(),
575 _ndc(ndc) {
576 assert(notify_done_closure() != NULL, "can't notify on NULL");
577 }
578 // Destructor-like method.
579 void destruct();
580 // Accessor.
581 NotifyDoneClosure* notify_done_closure() const { return _ndc; }
582 };
583
584 // A WaitForBarrierGCTask is a BarrierGCTask
585 // with a method you can call to wait until
586 // the BarrierGCTask is done.
587 // This may cover many of the uses of NotifyingBarrierGCTasks.
588 class WaitForBarrierGCTask : public BarrierGCTask {
589 private:
590 // Instance state.
591 Monitor* _monitor; // Guard and notify changes.
592 bool _should_wait; // true=>wait, false=>proceed.
593 const bool _is_c_heap_obj; // Was allocated on the heap.
594 public:
595 virtual char* name() { return (char *) "waitfor-barrier-task"; }
596
597 // Factory create and destroy methods.
598 static WaitForBarrierGCTask* create();
599 static WaitForBarrierGCTask* create_on_c_heap();
600 static void destroy(WaitForBarrierGCTask* that);
601 // Methods.
602 void do_it(GCTaskManager* manager, uint which);
603 void wait_for();
604 protected:
605 // Constructor. Clients use factory, but there might be subclasses.
606 WaitForBarrierGCTask(bool on_c_heap);
607 // Destructor-like method.
608 void destruct();
609 // Accessors.
610 Monitor* monitor() const {
611 return _monitor;
612 }
613 bool should_wait() const {
614 return _should_wait;
615 }
616 void set_should_wait(bool value) {
617 _should_wait = value;
618 }
619 bool is_c_heap_obj() {
620 return _is_c_heap_obj;
621 }
622 };
623
624 class MonitorSupply : public AllStatic {
625 private:
626 // State.
627 // Control multi-threaded access.
628 static Mutex* _lock;
629 // The list of available Monitor*'s.
630 static GrowableArray<Monitor*>* _freelist;
631 public:
632 // Reserve a Monitor*.
633 static Monitor* reserve();
634 // Release a Monitor*.
635 static void release(Monitor* instance);
636 private:
637 // Accessors.
638 static Mutex* lock() {
639 return _lock;
640 }
641 static GrowableArray<Monitor*>* freelist() {
642 return _freelist;
643 }
644 };
645
646 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_GCTASKMANAGER_HPP